This invention relates to a package which is highly sealable, which can be opened easily by peeling and which can accommodate foods, medicines, electric parts and any other articles.
Heretofore, in order to open a hermetically sealed pouch having a content heat-sealed therein, one of the following methods was used:
(1) breaking the heat-sealed portions, or PA1 (2) ripping open the pouch from a notch or similar rip-starting mark formed in the pouch beforehand.
In order to form an opening according to the former method, the heat-sealing strength has to be rather low. Thus, a package opened by this method is not suitable for containing liquids or heavy substances nor is it suitable as a package to be subjected to a retorting treatment. Also, since the heat-sealing strength along the portion where the pouch is to be opened is not uniform, the pouch may not be opened smoothly. If one tries to open the pouch by force, it may get broken, and the contents may scatter about and become useless.
With the latter method, ripping requires a considerable force and it is difficult to rip open the pouch in a desired direction, i.e. to open the pouch at a desired portion. This increases the possibility of the scattering of contents. In order to solve this problem, various proposals have been made, e.g. using a material which is orientated strongly in a direction substantially parallel to the direction in which the pouch is intended to be torn apart, forming perforations to restrict the tear direction, or using a plastic reinforcing material. These measures all push up the cost of the pouch and are still not very effective.